1. Field of the Invention
This invention is a circuit for accurately measuring any quantifiable signal quality parameter, such as BER or E.sub.b /N.sub.o, of any antipodal data stream, such as FSK or PSK modulated data.
2. Description of the Prior Art
A prior art search uncovered the following U.S. patent references:
U.S. Pat. No. 4,234,954 estimates BER by counting the number of instances in which the received signal deviates more than twice the normal amount from the reference level. It is not adaptive as in the present invention, nor does it compare live measurements with stored experimental data.
U.S. Pat. No. 3,721,959 is not adaptive as in the present invention, and does not give the actual value of signal quality as in the present invention, but rather makes a good/bad determination.
U.S. Pat. Nos. 4,100,531; 3,978,406; 3,911,395 and 3,824,548 require the transmission of coding information over the data link, unlike the present invention which requires no such coding information.
U.S. Pat. Nos. 4,091,240 and 4,091,239 monitor BER performance by using two demodulators. The present invention requires only one demodulator.
U.S. Pat. No. 4,110,691 detects errors in a seven level correlative waveform, unlike the antipodal data stream of the present invention.
U.S. Pat. Nos. 4,167,701 and 4,118,686 perform error corrections, unlike the present invention.